#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>
#include <errno.h>

int main()
{
	pthread_mutex_t mtx = PTHREAD_MUTEX_INITIALIZER;
	if (pthread_mutex_unlock(&mtx)) {
		perror("pthread_mutex_unlock");
	}

	pthread_mutex_t mtxerr = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP;
	if (pthread_mutex_unlock(&mtxerr)) {
		perror("pthread_mutex_unlock 2");
	}

	pthread_mutex_t mtxrec = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
	if (pthread_mutex_unlock(&mtxrec)) {
		perror("pthread_mutex_unlock 3");
	}

	return 0;
}